In an informal question-and-answer format, some big-name Republicans and possible 2016 presidential candidates discussed issues affecting the agriculture industry at the Iowa Ag Summit.Watch this storyOne of the biggest issues discussed at Saturday's summit was whether the federal government should require labeling foods that contain GMOs.Former Florida Gov. Jeb Bush said GMOs allow farmers to deal with droughts and produce higher yields.“We should not try to make it harder for that kind of innovation to exist. We should celebrate it ... I think that's a solution to a problem that doesn't exist,” Bush said.Texas Sen. Ted Cruz told the crowd of hundreds that is up to consumers to decide what they want to buy.“People who decide that's what they want, they can pay for it already. But, we shouldn't let anti-science zealotry shut down the ability to produce low cost, quality food for billions across the globe,” Cruz said.The potential presidential candidates also discussed the wind tax credit and the renewable fuel standard, an important program for Iowa's ethanol industry.“The worst we can do with any government program, government subsidy, government anything is give it eternal life. I think the only living beings on Earth that should have eternal life are human beings and dogs. Nobody else should have eternal life,” said former Arkansas Gov. Mike Huckabee.Wisconsin Gov. Scott Walker made it clear he supports a free and open market with as little interference from the federal government as possible.“It’s an access issue. It's something I’m willing to go forward on continuing the renewable fuel standard and pressing the EPA to make sure there's certainty, in terms of the blend levels or in terms of the levels set,” Walker said.Sen. Marco Rubio of Florida and Donald Trump were scheduled to speak today but did not make an appearance.Former Iowa Lt. Gov. Patty Judge was the only Democrat to speak at the summit, but there were several others who met at the Marriott Hotel in downtown Des Moines.

“We should not try to make it harder for that kind of innovation to exist. We should celebrate it ... I think that's a solution to a problem that doesn't exist,” Bush said.

Texas Sen. Ted Cruz told the crowd of hundreds that is up to consumers to decide what they want to buy.

“People who decide that's what they want, they can pay for it already. But, we shouldn't let anti-science zealotry shut down the ability to produce low cost, quality food for billions across the globe,” Cruz said.

The potential presidential candidates also discussed the wind tax credit and the renewable fuel standard, an important program for Iowa's ethanol industry.

“The worst we can do with any government program, government subsidy, government anything is give it eternal life. I think the only living beings on Earth that should have eternal life are human beings and dogs. Nobody else should have eternal life,” said former Arkansas Gov. Mike Huckabee.

Wisconsin Gov. Scott Walker made it clear he supports a free and open market with as little interference from the federal government as possible.

“It’s an access issue. It's something I’m willing to go forward on continuing the renewable fuel standard and pressing the EPA to make sure there's certainty, in terms of the blend levels or in terms of the levels set,” Walker said.

Sen. Marco Rubio of Florida and Donald Trump were scheduled to speak today but did not make an appearance.

Former Iowa Lt. Gov. Patty Judge was the only Democrat to speak at the summit, but there were several others who met at the Marriott Hotel in downtown Des Moines.